The chemical constituents were isolated by various chromatography techniques and their structures were elucidated on the basis of spectroscopic data. The immunomodulatory activity of some compounds was examined by Balb/c mouse spleen lymphocyte proliferation through MTT. Twelve known flavonoids were isolated and identified as: quercetin-3-O-α±-L-ara-binfuranside (1), quercetin-3-O-α±-L-rhamnopyranoside (2), trans-taxifolin-3-O-α±- arabinopyranoside (3), astilbin (4), 3-Orhamnoside engeletin (5), naringenin (6), (2S)-5,7,4'-Trihydroxy-8-methylflavanone (7), epicatechin- (2β??O??7,4β??8)-ent-epicatechin (8), proanthocyanidin A-l (9), bis-8, 8?2-catechiny-lmethane (10), catechin (11), and epicatechin (12). The results showed that compounds 8, 9, and 11 alone or combined with ConA or LPS could significantly enhance the proliferation of spleen lymphocytes in a certain dose range.